The Real Truth About How Much Water You Should Drink

Q: Do I really need to drink eight glasses of water every day to be hydrated?

A: The Institutes of Medicine recommends about 9 cups of total beverages a day for women, and about 13 cups for men. So if you’re looking for a hard number to hang your hat on, the old adage about drinking at least eight glasses of water every day will likely get you there.

Q: Can’t I just drink when I’m thirsty?

A: Thirst is not an especially reliable indicator of whether your body is hydrated enough, so don’t wait for a dry, sticky mouth to tell you that you need fluids—stay ahead of your thirst by drinking regularly during the day.

Q: Does it have to be water, or can I drink other beverages instead?

A: Fluids whose No. 1 ingredient is water, such as coffee, tea, juice, milk, soda and soups, will all contribute to your overall fluid intake. The fluids in fruits and vegetables you eat count too.

Bust most of us would probably do ourselves a favor by drinking more water, rather than other beverages. Diet soda, for example, has a myriad of additives and chemicals.

Q: What about caffeinated drinks—won’t they dehydrate me instead?

A: Not unless you’re consuming excessive amounts, such as starting the morning with an entire pot of coffee or pounding down high-caffeine energy drinks all day. If you’re drinking caffeinated beverages in normal amounts, your body will still retain most of the water from them.

Q: Why does being hydrated matter anyway?

A: Consuming adequate fluid, along with a high-fiber diet, keeps your intestinal tract operating at its peak performance. And since the gut is probably the main influence on your total functional health, you want to have a highly efficient gut.